/**
 * Copyright 2016- the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.inmorn.orm.mybatis;
import static java.lang.reflect.Proxy.newProxyInstance;
import static org.apache.ibatis.reflection.ExceptionUtil.unwrapThrowable;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.util.List;
import java.util.Map;

//import org.apache.ibatis.exceptions.PersistenceException;
import org.apache.ibatis.executor.BatchResult;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

/**
 * @author Jeff.Li
 * @date 2016年11月9日
 * 注:扩展原mybatis-spring.jar
 */
public class SqlSessionTemplate implements SqlSession {

	private final SqlSessionFactory sqlSessionFactory;

	private final ExecutorType executorType;

	private final SqlSession sqlSessionProxy;

//	private final PersistenceExceptionTranslator exceptionTranslator;

	/**
	 * Constructs a Spring managed SqlSession with the {@code SqlSessionFactory}
	 * provided as an argument.
	 * 
	 * @param sqlSessionFactory
	 */
	public SqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
		this(sqlSessionFactory, sqlSessionFactory.getConfiguration()
				.getDefaultExecutorType());
	}

	/**
	 * Constructs a Spring managed SqlSession with the {@code SqlSessionFactory}
	 * provided as an argument and the given {@code ExecutorType}
	 * {@code ExecutorType} cannot be changed once the
	 * {@code SqlSessionTemplate} is constructed.
	 * 
	 * @param sqlSessionFactory
	 * @param executorType
	 */
//	public SqlSessionTemplate(SqlSessionFactory sqlSessionFactory,
//			ExecutorType executorType) {
//		this(sqlSessionFactory, executorType, new MyBatisExceptionTranslator(
//				sqlSessionFactory.getConfiguration().getEnvironment()
//						.getDataSource(), true));
//	}

	/**
	 * Constructs a Spring managed {@code SqlSession} with the given
	 * {@code SqlSessionFactory} and {@code ExecutorType}. A custom
	 * {@code SQLExceptionTranslator} can be provided as an argument so any
	 * {@code PersistenceException} thrown by MyBatis can be custom translated
	 * to a {@code RuntimeException} The {@code SQLExceptionTranslator} can also
	 * be null and thus no exception translation will be done and MyBatis
	 * exceptions will be thrown
	 * 
	 * @param sqlSessionFactory
	 * @param executorType
	 * @param exceptionTranslator
	 */
	public SqlSessionTemplate(SqlSessionFactory sqlSessionFactory,
			ExecutorType executorType) {

		if(sqlSessionFactory == null){
			throw new IllegalArgumentException("Property 'sqlSessionFactory' is required");
		}
		if(executorType == null){
			throw new IllegalArgumentException("Property 'executorType' is required");
		}

		this.sqlSessionFactory = sqlSessionFactory;
		this.executorType = executorType;
//		this.exceptionTranslator = exceptionTranslator;
		this.sqlSessionProxy = (SqlSession) newProxyInstance(
				SqlSessionFactory.class.getClassLoader(),
				new Class[] { SqlSession.class }, new SqlSessionInterceptor());
	}

	public SqlSessionFactory getSqlSessionFactory() {
		return this.sqlSessionFactory;
	}

	public ExecutorType getExecutorType() {
		return this.executorType;
	}

//	public PersistenceExceptionTranslator getPersistenceExceptionTranslator() {
//		return this.exceptionTranslator;
//	}

	/**
	 * {@inheritDoc}
	 */
	public <T> T selectOne(String statement) {
		return this.sqlSessionProxy.<T> selectOne(statement);
	}

	/**
	 * {@inheritDoc}
	 */
	public <T> T selectOne(String statement, Object parameter) {
		return this.sqlSessionProxy.<T> selectOne(statement, parameter);
	}

	/**
	 * {@inheritDoc}
	 */
	public <K, V> Map<K, V> selectMap(String statement, String mapKey) {
		return this.sqlSessionProxy.<K, V> selectMap(statement, mapKey);
	}

	/**
	 * {@inheritDoc}
	 */
	public <K, V> Map<K, V> selectMap(String statement, Object parameter,
			String mapKey) {
		return this.sqlSessionProxy.<K, V> selectMap(statement, parameter,
				mapKey);
	}

	/**
	 * {@inheritDoc}
	 */
	public <K, V> Map<K, V> selectMap(String statement, Object parameter,
			String mapKey, RowBounds rowBounds) {
		return this.sqlSessionProxy.<K, V> selectMap(statement, parameter,
				mapKey, rowBounds);
	}

	/**
	 * {@inheritDoc}
	 */
	public <E> List<E> selectList(String statement) {
		return this.sqlSessionProxy.<E> selectList(statement);
	}

	/**
	 * {@inheritDoc}
	 */
	public <E> List<E> selectList(String statement, Object parameter) {
		return this.sqlSessionProxy.<E> selectList(statement, parameter);
	}

	/**
	 * {@inheritDoc}
	 */
	public <E> List<E> selectList(String statement, Object parameter,
			RowBounds rowBounds) {
		return this.sqlSessionProxy.<E> selectList(statement, parameter,
				rowBounds);
	}

	/**
	 * {@inheritDoc}
	 */
	public void select(String statement, ResultHandler handler) {
		this.sqlSessionProxy.select(statement, handler);
	}

	/**
	 * {@inheritDoc}
	 */
	public void select(String statement, Object parameter, ResultHandler handler) {
		this.sqlSessionProxy.select(statement, parameter, handler);
	}

	/**
	 * {@inheritDoc}
	 */
	public void select(String statement, Object parameter, RowBounds rowBounds,
			ResultHandler handler) {
		this.sqlSessionProxy.select(statement, parameter, rowBounds, handler);
	}

	/**
	 * {@inheritDoc}
	 */
	public int insert(String statement) {
		return this.sqlSessionProxy.insert(statement);
	}

	/**
	 * {@inheritDoc}
	 */
	public int insert(String statement, Object parameter) {
		return this.sqlSessionProxy.insert(statement, parameter);
	}

	/**
	 * {@inheritDoc}
	 */
	public int update(String statement) {
		return this.sqlSessionProxy.update(statement);
	}

	/**
	 * {@inheritDoc}
	 */
	public int update(String statement, Object parameter) {
		return this.sqlSessionProxy.update(statement, parameter);
	}

	/**
	 * {@inheritDoc}
	 */
	public int delete(String statement) {
		return this.sqlSessionProxy.delete(statement);
	}

	/**
	 * {@inheritDoc}
	 */
	public int delete(String statement, Object parameter) {
		return this.sqlSessionProxy.delete(statement, parameter);
	}

	/**
	 * {@inheritDoc}
	 */
	public <T> T getMapper(Class<T> type) {
		return getConfiguration().getMapper(type, this);
	}

	/**
	 * {@inheritDoc}
	 */
	public void commit() {
		throw new UnsupportedOperationException(
				"Manual commit is not allowed over a Spring managed SqlSession");
	}

	/**
	 * {@inheritDoc}
	 */
	public void commit(boolean force) {
		throw new UnsupportedOperationException(
				"Manual commit is not allowed over a Spring managed SqlSession");
	}

	/**
	 * {@inheritDoc}
	 */
	public void rollback() {
		throw new UnsupportedOperationException(
				"Manual rollback is not allowed over a Spring managed SqlSession");
	}

	/**
	 * {@inheritDoc}
	 */
	public void rollback(boolean force) {
		throw new UnsupportedOperationException(
				"Manual rollback is not allowed over a Spring managed SqlSession");
	}

	/**
	 * {@inheritDoc}
	 */
	public void close() {
		throw new UnsupportedOperationException(
				"Manual close is not allowed over a Spring managed SqlSession");
	}

	/**
	 * {@inheritDoc}
	 */
	public void clearCache() {
		this.sqlSessionProxy.clearCache();
	}

	/**
	 * {@inheritDoc}
	 * 
	 */
	public Configuration getConfiguration() {
		return this.sqlSessionFactory.getConfiguration();
	}

	/**
	 * {@inheritDoc}
	 */
	public Connection getConnection() {
		return this.sqlSessionProxy.getConnection();
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @since 1.0.2
	 * 
	 */
	public List<BatchResult> flushStatements() {
		return this.sqlSessionProxy.flushStatements();
	}

	/**
	 * Proxy needed to route MyBatis method calls to the proper SqlSession got
	 * from Spring's Transaction Manager It also unwraps exceptions thrown by
	 * {@code Method#invoke(Object, Object...)} to pass a
	 * {@code PersistenceException} to the
	 * {@code PersistenceExceptionTranslator}.
	 */
	private class SqlSessionInterceptor implements InvocationHandler {
		public Object invoke(Object proxy, Method method, Object[] args)
				throws Throwable {
			SqlSession sqlSession = SqlSessionTemplate.this.sqlSessionFactory
					.openSession(SqlSessionTemplate.this.executorType);
			try{
				Object result = method.invoke(sqlSession, args);
				return result;
			}catch(Throwable t){
				Throwable unwrapped = unwrapThrowable(t);
				throw unwrapped;
			}finally{
				if (sqlSession != null) {
					sqlSession.close();
				}
			}
			/**
			SqlSession sqlSession = getSqlSession(
					SqlSessionTemplate.this.sqlSessionFactory,
					SqlSessionTemplate.this.executorType,
					SqlSessionTemplate.this.exceptionTranslator);
			try {
				Object result = method.invoke(sqlSession, args);
				if (!isSqlSessionTransactional(sqlSession,
						SqlSessionTemplate.this.sqlSessionFactory)) {
					// force commit even on non-dirty sessions because some
					// databases require
					// a commit/rollback before calling close()
					sqlSession.commit(true);
				}
				return result;
			} catch (Throwable t) {
				Throwable unwrapped = unwrapThrowable(t);
				if (SqlSessionTemplate.this.exceptionTranslator != null
						&& unwrapped instanceof PersistenceException) {
					// release the connection to avoid a deadlock if the
					// translator is no loaded. See issue #22
					closeSqlSession(sqlSession,
							SqlSessionTemplate.this.sqlSessionFactory);
					sqlSession = null;
					Throwable translated = SqlSessionTemplate.this.exceptionTranslator
							.translateExceptionIfPossible((PersistenceException) unwrapped);
					if (translated != null) {
						unwrapped = translated;
					}
				}
				throw unwrapped;
			} finally {
				if (sqlSession != null) {
					closeSqlSession(sqlSession,
							SqlSessionTemplate.this.sqlSessionFactory);
				}
			}
			 **/
		}
	}

}
